Black mollies can be prolific breeders. According to what I’ve heard, they can produce over 100 fry in a single breeding season. Black mollies are tough and resilient, but they need special care during pregnancy. Your black molly fish pregnant will give birth to premature fry that won’t survive.
This blog will cover everything you need to know about pregnant black moly fish.
Before we begin, please watch this video of a black Molly Fish giving birth. So fascinating!
How Long Are Black Molly Fish Pregnant For?
Black mollies can become pregnant anywhere from 40 to 70 days, just like the rest of the molly species. They are much longer than other tropical livebearers such as guppies or swordtails.
They are twice as likely to be pregnant than guppies, who have gestation periods of around 21-35 days.
The length of a black molly’s pregnancy depends on many factors, including the fish’s size and age, water conditions, diet, stress levels, and weight.
Black mollies, just like mammals can give birth to preterm fry if they’ve miscarried or had an abortion.
How Often Can Black Molly Fish Get Pregnant?
Black mollies can be prolific breeders. They can reproduce as often as once in 30 to 45 days. However, this is dependent on variables such as age, weight, experience, diet, stress level, and other factors.
At What Age Can Black Molly Fish Produce Babies?
At 4-5 month old, black mollies reach sexual maturity. Males mature slightly faster than females.
You don’t want tiny fry to overrun your tank. It is best to separate males from females before they reach sexual maturity.
Let me quickly show you how to distinguish a male from a female black molly.
Is My Black Molly Male Or Female?
The male black mollies have a modified anal fin, known as a “gonopodium”, which is pointy and thin. The female’s anal fin, on the other hand is shorter, triangular and almost like a fan.
Can Black Mollies Give Birth Without Male?
Yes, black moles can give birth without the presence of a male. This is because the females can keep sperm in their system for several months after previous copulations.
Even if she doesn’t have a male in her tank, she can still use her stored sperm for fertilization and to produce babies.
Don’t be surprised to see tiny black molly fry in an all-female tank one sunny day.
How Many Babies Do Black Molly Fish Have?
Black mollies can produce 40-100 fry during one spawning season. Mothers who are inexperienced often give birth to fewer fry.
As she gets older and becomes more adept at being pregnant, her brood size will rise.
The age and size factors of fish play an important role in the number of children they produce.
Black Molly Pregnancy Stages
The pregnancy of a black molly fish can be divided into five stages, starting with copulation and ending with the birth of the fry. These are:
- Conception
- Formation of an Embryo
- Fry
- Pre-birthing Stage
- Birth
Conception
Mollies are very prolific breeders. The little fry will soon arrive if there are fish of both genders in the tank. Mollies form polygamous pairs.
Males will fertilize every female they can. They will even attempt to fertilize females who have been fertilized before.
Males are known to bully and harass females in order to induce conception. It’s how it is. There’s nothing you can do.
Once he has coaxed the woman, he will release milt from his gonopodium and into the female’s sperm opening.
Formation of Embryo
Fertilized eggs will become embryos. Low calcium levels won’t fertilize eggs that aren’t fertilized. They will keep their original translucent yellow color, round shape and size.
Unfertilized eggs can be either ‘aborted’ individually or at the time of your black molly giving birth. This is how you get the illusion that the molly has laid eggs.
You can see the embryo’s growth through the gravid spot’s thin walls after 7-10 days.
Development Of Fry
The body of the black molly expands as the embryos become little fry. In one week, for example, the abdominal volume can grow up to 25%.
Every embryo/fry has the same nutritional elements that their mother initially provided. It is what they rely upon for their nutrition.
Pre-Birthing Stage
You can see tiny black spots for the eyes as the fry grow through the gravid spots.
This stage is where the black molly prepares herself mentally and physically to give birth.
A few days before her due date, she will have a bulge under her gills that will make her outline square rather than round.
Gravid spot will be more prominent than ever.
The perfectly formed fry is ready to be released. They will be in a semicircular position.
Birth
Delivery can take anywhere from a few hours up to several days depending on how many fry your black moly has.
The fry are born one at a.m. with their tails coming out first.
The fry will fall through the water a few inches once it is out. However, it will quickly rise up and find cover to protect its head. Amazing, isn’t it?
The fry will seek refuge in the rocks and sand if there is no other hiding place nearby. As they gain strength, they may remain motionless for a short time.
As black mollies can eat their babies, you must immediately remove the mother from her breeding tank. Yikes!
Black Molly Fish Pregnant Signs
These are the five most important signs that a pregnant black moly fish is in good health:
- A swollen, rounded stomach
- Irritatable behavior
- A change of appetite
- Prominent Gravid Spot
- A higher affinity for warmth
Swollen And Rounded Belly
The female black molly’s body will expand to accommodate up to 100 offspring. Her body will be unmistakably swollen and develop a round appearance.
She will look almost full, especially around the stomach.
The matriarch will create a bulge just below the gill when it is near to delivering the fry. This will give the area an almost squarish appearance.
Aloof And Irritable Behavior
Molly temperaments are friendly and social. A female molly may appear more distant and irritable during pregnancy.
She may become more tolerant of other fish and even resort to aggression in her anger. She will, however, prefer to be alone.
She will be more active a few days before her due date as she searches for peaceful, quiet areas to give birth.
A Change in Appetite
Mollies are very hungry, to be honest. A pregnant molly may eat more than normal. She needs energy to counter all the changes in her body.
She may stop eating after the last trimester. Even if you offer her your favorite food, she will not be interested.
This is a good sign that the fry will soon arrive.
Prominent Gravid Spot
Gravid spot refers to the darkened area near the base the anal fin that is caused by stretching of the peritoneal walls. The gravid spot can be compared to the womb in a sense.
The egg is not attached to the body of the black molly and she does not feed it directly, unlike mammals.
As the pregnancy progresses, the gravid spot becomes darker and larger. However, it might not be obvious right away in black mollies.
An Increased Affinity For Warmth
Pregnant mollies must maintain a constant temperature throughout their pregnancy, preferably between 77 and 80 degrees Fahrenheit.
Temperatures below 68 degrees Fahrenheit can prolong the gestation period. This can pose a risk to your black molly.
If your molly seems to be constantly around the temperature stabilizer or heating system, it could indicate that your molly may be expecting.
If you have an overhead UV lamp for the tank, the pregnant black mole may hover closer to the surface.
Black Molly Pregnant Or Bloated?
A black molly fish with a prominent gravid area and reclusiveness could be a sign that it’s pregnant. But if the fish doesn’t seem aloof or distant, but has a swollen appearance without a visible gravid mark, this could indicate that the fish is bloated.
If this is the case, you can fast your fish for a while. Then, you can break the fast by eating boiled and skinned beans. Peas are rich in fiber which will aid in digestion.
Final Words: Pregnant Black Molly Fish
A black molly fish’s average gestation time is between 40 and 70 days. This is twice the gestation time of a guppy.
It is important to consider the female’s age and size as well as her stress level when determining how long the gestation period will last and how many fry she will produce. The number of fry she can give birth to is anywhere from 40-100.
She will display physical signs such as a prominent gravid area and swelling when she is pregnant. She may also be more aggressive and eat more than usual.